dev.capabilities: Query Capabilities of the Current Graphics Device

Description

Usage

Arguments

what

a character vector partially matching the names of the
components listed in section ‘Value’, or NULL which
lists all available capabilities.

Details

The capabilities have to be specified by the author of the graphics
device, unless they can be deduced from missing hooks. Thus they will
often by returned as NA, and may reflect the maximal
capabilities of the underlying device where several output formats are
supported by one device.

Most recent devices support semi-transparent colours provided the
graphics format does (which PostScript does not). On the other hand,
relatively few graphics formats support (fully or semi-) transparent
backgrounds: generally the latter is found only in PDF and PNG plots.

Value

A named list with some or all of the following components, any of which may
take value NA:

semiTransparency

logical: Does the device support
semi-transparent colours?

transparentBackground

character: Does the device support
(semi)-transparent backgrounds? Possible values are "no",
"fully" (only full transparency) and "semi"
(semi-transparent background colours are supported).

rasterImage

character: To what extent does the device support
raster images as used by rasterImage and
grid.raster? Possible values "no", "yes" and
"non-missing" (support only for arrays without any missing
values).

capture

logical: Does the current device
support raster capture as used by grid.cap?

locator

logical: Does the current device
support locator and identify?

events

character: Which events can be generated on this device?
Currently this will be a subset of c("MouseDown",
"MouseMove", "MouseUp", "Keybd"), but other events may be
supported in the future.